It has been claimed that DNA testing can provide an indication of alleles associated with thyroglobulin gene polymorphism. However, Rincker et al. (2006) found the GeneSTAR marbling marker was not associated with intramuscular fat deposition in early weaned steers fed a high-concentrate diet and the thyroglobulin gene was not associated with other carcass, performance parameters, or marbling expected progeny difference. Similarly, Van Eenennaam et al. (2007) could not validate the utility of the markers.
By contrast, US 2008/0010696 shows that SCD SREB has relevance in marbling in Japanese cattle but not others. SREBP is a transcription factor which regulates gene expression levels of stearoyl-CoA desaturase (SCD1) and other genes relevant to lipid and fatty acid metabolism in tissue (Hoashi et al., 2007). The content of unsaturated fatty acid in beef is an important factor in taste and texture (Hoashi et al., 2007; EP 1845159) and the degree of marbling. A recent study revealed that the high SCD activities were positively correlated with beef marbling score, amount of monounsaturated fatty acid and conjugated linoleic acid, but negatively correlated with the amount of saturated fatty acid (Jiang et al., 2008).
U.S. Pat. No. 7,157,231 shows that bovine growth hormone (GH Exon 5) has an important role with the B & C alleles contributing to marbling, again this effect is confined to Japanese cattle. U.S. Pat. No. 7,238,479 shows that genetic testing for alleles of the gene encoding calcium activated neutral protease effecting meat tenderness in bovines is useful in selective breeding. US 2004/0261138 shows that genetic markers in the porcine melanocortin-4 receptor (MC4R) gene are associated with meat quality.
However, there is a need for further methods of genetic analysis for identifying livestock with desirable traits.